Search of quicksands and karsts

     There, where soils have the increased permeability, namely, in zones of tectonic disturbances the quicksands and karsts are formed. Karsts are formed there where in conditions of burial the carbonates migrate acid groundwaters. The nature of an origin of quicksands is not clear, but, as well as karsts, they represent a half-liquid substance which is in solid environment.

     On the SSP-section the quicksand (shown by blue color) is found out by search along the Stachek prospectus , in St. Petersburg, along a line of the future viaduct. The funnel-shaped object being the indicator of a tectonic disturbance, is shown by red color. As shows our experience, quicksands and karsts are always formed at edge of a tectonic disturbance.
     At coming of a support of a viaduct into a quicksand it is necessary to expect the accelerated immersing of this support in a ground.